var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');

var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');
app.use(logger('dev'));
// app.use(express.json());
// app.use(express.urlencoded({extended: false}));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

const {createProxyMiddleware} = require('http-proxy-middleware');
var options = {
    target: 'http://127.0.0.1:3001', // 后端目标服务器地址
    changeOrigin: true, // 默认 false，是否需要改变原始主机头为目标 URL
    pathRewrite: {
        '^/api': '/', // 所有以 "/api" 开头的请求，"/api" 都会重写为 "/",简单来说，就是通过这个/api,区分到底是代理服务器本地的请求，还是需要进行转发到后端目标服务器的请求
    }
};

// 代理服务器转发请求
app.use("/api", createProxyMiddleware(options));

// catch 404 and forward to error handler
app.use(function (req, res, next) {
    next(createError(404));
});

// error handler
app.use(function (err, req, res, next) { // set locals, only providing error in development
    res.locals.message = err.message;
    res.locals.error = req.app.get('env') === 'development' ? err : {};

    // render the error page
    res.status(err.status || 500);
    res.render('error');
});

module.exports = app;
